The invention relates generally to dietary sources of metals and carboxylates and, more specifically, to a method for the production of metal carboxyl ate and its use as a source of dietary supplement.
Dietary minerals, including iron, copper, manganese, magnesium, selenium, and zinc, are essential trace elements in human and animal nutrition and the deficiency of one or more of these minerals is a common nutritional problem. However, the absorption of many of these minerals in the biological system is significantly higher if offered from an organic source. Organic minerals in the form of metal carboxylates are proven to have superior bioavailability in the biological system.
Bertsch et al. and Martinez et al. (U.S. Pat. No. 2,848,366; British Patent 1,328,494) reported the preparation of ferrous fumigate, in which the preferred water-soluble numeric salt, sodium fumigate was reacted with the preferred water-soluble ferrous salt, ferrous soleplate at high temperature (70° C. to 94° C.), in a displacement reaction to produce ferrous fumigate.
Other prior arts approaches involving the preparation of iron carboxyl ate salts include classical acid-base reaction (U.S. Pat. No. 5,795,615; U.S. Pat. No. 5,591,878; U.S. Pat. No. 4,700,000), and oxidation reaction (U.S. Pat. No. 2,904,573).
In the reported prior art processes which utilize the classical acid-base neutralization reaction, the acid component, carboxylic acid, was reacted with the base component, a basic metal salt of carbonate, hydroxide, or oxide, to produce metal carboxyl ate.
In the reported prior art process which utilizes the oxidation reaction, powdered iron is heated with a nonferrous acid citrate to produce the desired ferrous citrate complex, accompanied with an increase in the oxidation state of iron from 0 to 2+, corresponding to an oxidation of iron to ferrous iron, respectively.
The present invention discloses a process for the preparation of metal carboxylates utilizing a different approach from those of the reported prior art. An acid-base-like reaction route is utilized in the preparation of metal carboxyl ate, in which the acid and base properties of the starting materials are different from those previously reported in prior arts, for example, U.S. Pat. Nos. 5,795,615, 5,591,878, and 4,700,000.
The basic component used in the present invention is an ammonium salt of carboxyl ate and the acid component is a metal salt having the property of a Lewis acid, and the reaction proceeds at controlled temperatures.